Several authentication methods using an image of a blood vessel pattern of a human hand have been proposed recently as one way of organism authenticating. In JP, A, H08-508419, for example, an apparatus for authenticating a person by using a vein image of the back of a human hand is presented.
Such conventional organism authenticating methods as exemplified above, however, have several drawbacks; it is difficult to get a clear blood vessel image, the apparatus size cannot be small enough for actual applications, and there is a possibility that a wrong person is authenticated as the principal.